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Essential Biology E4: Neurotransmitters and Synapses
Make sure you have reviewed Nerves, Hormones and Homeostasis before starting.
1. Distinguish between excitatory and inhibitory pre-synaptic neurons:
Excitatory
Effect on post-synaptic
transmissions
Inhibitory
Stimulates an AP in the
post-synaptic neuron
NT binds to receptors.
Potassium gates open.
K+ flows out.
Post-synaptic neuron
hyperpolarizes.
AP is not generated.
Method of action
(including ion)
Graph of membrane
potential
Example
neurotransmitters
2. Draw a diagram of the dendritic end of a neuron, labeling the axon hillock and showing the
direction of nerve impulses coming into the neuron. What is the function of the axon hillock?
3. Explain how decision-making takes place in the CNS, including the interactions between
excitatory and inhibitory presynaptic neurons and the importance of threshold.
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology E4: Neurotransmitters and Synapses
4. Distinguish between spatial and temporal summation.
5. Define psychoactive drug.
6. Explain how psychoactive drugs affect post-synaptic transmissions through either mimicking or
blocking normal neurotransmitters.
7. Explain how this effect on NTs and post-synaptic transmission results in behavioural changes,
with reference to ‘normal behaviour.
8. Categorise the following drugs as either excitatory or inhibitory:
Alcohol, THC (marijuana), nicotine, amphetamines, benzodiazepines, cocaine.
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology E4: Neurotransmitters and Synapses
Excitatory:
Inhibitory:
9. Visit the following websites to find out more about how THC and cocaine affect brain activity,
including the methods of action and effects on mood and behaviour.
The Brain from Top to Bottom: http://thebrain.mcgill.ca/flash/index_i.html
Harvard MCB outreach: http://outreach.mcb.harvard.edu/animations/synapse.swf
Jellinek – Drugs and the Brain: http://www.jellinek.nl/brain/index.html
THC
Cocaine
10. Also visit the website Learn.Genetics and find out more about addiction:
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology E4: Neurotransmitters and Synapses
http://learn.genetics.utah.edu/content/addiction/
a. Discuss the causes of addiction:
i.
Genetics - Remember: Susceptibility does not mean inevitability
ii.
Psychosocial factors
iii.
Dopamine and reward pathways
Non-exam discussions (but really interesting anyway):
b. Discuss the social, economic and health impacts of addiction.
c. Discuss the ethical considerations regarding the legislation of drugs and some methods used
to counsel and treat drug addiction.
TOK –link reading:
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology E4: Neurotransmitters and Synapses
Leader of advisory panel on drug safety sacked for disagreeing with UK government:
http://www.badscience.net/2009/11/the-nutt-sack-affair-part-493/
Read around the topic, and then answer these questions:
1. How does this story show the conflict between science and politics?
2. What do you feel the respective roles of science and politics should be in the government of a
country?
3. Suggest reasons why some drugs which are clearly very harmful, such as tobacco and alcohol,
are still legal in many countries.
4. If you were to form a new country and write a whole new set of drug laws, which would you
make illegal or legal and why? Upon which sources of evidence would you rely in order to make
your decisions? How would you balance political pressures with scientific evidence?
Find out more about drug laws and the rationale behind them in your own country and the countries
you visit or live in.
Remember – regardless of your own opinion on drug laws, if you are caught
breaking the law wherever you are, penalties can be very severe.
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com